Fluid pressure motor



W. H. GLASS FLUID PRESSURE MOTOR Filed March 51, 1945 March 7, 1944HGIGSS BY @if ATTORNEY flatedod Mar. 7, 1944' FLUID PRESSURE MOTORWilliam H. Glass, Pittsburgh, Pa., asslgnor to The i Westinghouse AirBrake Company, Wilmerding,

a corporation of Pennsylvania Application March 31, 1943. Serial N0.481,194 6 Claims. (Cl. 121-41) This invention relates to iluid pressuremotors and more particularly to the type arranged to operate inaccordance with selected operations of a manual controller forcontrolling the positioning or operation of a device such as a clutch.

In the copending application of Roy R. Stevens, Serial No. 448,167,filed June 23, 1942, and assigned to the assignee of the presentapplication, there is disclosed an apparatus embodying a motor which isoperable by fluid pressure to control the operation of a clutch controlelement. vThe clutch controlled by the element is of the type having aforward drive condition, a reverse 'drive condition, and a neutralnon-driving condition, and said element has three positions, namely,forward, reverse, and neutral, for correspondingly conditioning theclutch.

The fluid motor for the clutch control element embodies a power pistonhaving forward, reverse, and neutral positions, a pilot piston havinglike positions, and a control valve device controlled jointly by thepower and pilot pistons. The pilot piston is movable by iluid pressurerelative to the power piston to actuate the control valve device forsupplying fluid under pressure from a communication to either one sideor the other of the power piston for causing movement thereof to movethe clutch control element to either one or the other of its drivepositions. A cut-off valve device, controlled in one of the embodimentsby the pilot piston, controls the supply of fluidunder pressure to thecommunication leading to the control valve device. When the pilot pistonis between its forward and reverse positions, the cut-oil valve deviceis operative to supply fluid under pressure to the communication leadingto the control valve device, but upon movement of the pilot piston toeither oi' said positions the cutoil valve device operates to cut-oilthesupply of fluid pressure to said communication and to open same toatmosphere With one side or the other of the power piston open to thiscommunication at the time it is opened to atmosphere. the power pistonwill be relieved of actuating l'orce. and the lpurpose of this is torelieve the. shitting' bearings in the clutch of actuating force fromthe power piston after the clutch control element has been moved to thedesireddriving position.- l

In order to insure that the power piston will not be relieved ofactuating force prior to obtain- 'ing the desired positioning .of theclutch control element. initial movement of the pilot' piston towardeither its forward or reverse positions is limited to a degree sumcientto operate the control valve device to open the uid pressure supplylcommunication to the selected side of the power piston, butinsufilcient to cause operation of the cut-oil valve device to open saidcommunication to atmosphere. Further movement of the pilot piston thenoccurs along with the power piston which prevents the pilot pistonobtaining its forward or reverse position substantially ahead of thepower piston obtaining its corresponding position, which, in combinationwith other arrangements, insures that the cut-oil valve device will notoperate to relievethe power piston of actuating force until after theclutch control element has been positioned as desired.

One object of the present invention is the provision of an improvedarrangement for limiting the initial movement of the pilot piston towardeither its forward position or lts reverse position 'to accomplish theresult just described.

In the above referred to copending application, thecontrol valve devicecomprises a lever which operates in a slot the opposite ends of whichconsuture stops for .umiung the man1 movement, `iust described, of thepilot piston. These stops are fixed according to the travel or movementoi' a certain clutch part, such as the driven part. Occasionally howevera clutch is found in use in which the driven part has less travel, inwhich casel the pilot piston of the fluid pressure motor above describedcannot move far enough to cause .operation of the cut-oil' valve deviceto relieve the power piston of actuating force after the clutch controlelement has been moved to itsforward or reverse position.

Another object of the invention is therefore the provision of a fluidpressure motor for a clutch or the like embodying means Afor regulatingthe initial movement of the pilot piston to any speciflc clutch, so asto insure intended operation of the cut-oil valve device.

Still another object'of the invention is the provision lof means 'forregulating the initial movement of the pilot piston toward either itsforward or reverse positions in accordance with the specific clutch towhich the motor is connected, which means are readily accessible andadjustable.

Other objects and vadvantages of the invention will be apparent from thefollowing more detailed description. v

In the accompanying drawing, Fig 1 isa sectional view, partly indiagrammatic-form, of a iluid motor embodying the invention; and Fig. 2is a sectional view taken on the line 2! in Fig. l.

Description y In the drawing, the reference numeral indicates a portionoi a clutch housing which may contain a clutch, such as above described.A rock shaft 2 is provided ior moving the driven part ot the clutch inhousing I to its diilerent positions and this shaft is operable by alever or arm 3 which has a i'orward" position, a reverse position, and aneutral or disengaged position for correspondingly positioning thedriven part oi the clutch. 'I'hese positions oi arm 3 are indicated bylegends in the drawing.

For selectively moving the clutch arm 3 to any one of its differentpositions, a fluid motor is provided which comprises a power portion 4,a pilot portion 5, a nuid pressure control mechanism 6, and a cut-ofi orunloading valve device 1.

The power portion 4 comprises a casing containing a piston I connectedto one end of a piston rod which extends through apressure head |2. Theouter end oi piston rod is pivotally connected by a bolt I3 to one endoi a link I4 the opposite end of which is adjustably connected by screwthreads to an eye bolt I5. The eye bolt I5 in turn is connected by a pinI6 to the end oi the clutch operating arm 3.

The power piston I0 has at one side a pressure chamber |1 provided forreceiving iluid under pressure to act on one side oi the piston, whileat the opposite side ot the piston is a pressure chamber I8 provided forreceiving fluid under pressure to act on the opposite side. When chamberI1 is supplied with uid under pressure and chamber |8 is open to theatmosphere, as will be later described. the piston I0 will move in thedirection of the right hand for thereby rocking the clutch arm 3 in thedirection toward "forward position. while when chamber |1 is open to theatmosphere and fluid is supplied to chamber |8 the piston I0 willoperate to move the clutch control arm 3 in the direction of reverse"position.

The iluid pressure control mechanism 6 is provided ior supplying iluidunder pressure to and releasing iluid under pressure from the twopressure chambers I1 and I8 for controlling operation of the piston |0to position the clutchrarm 3. This mechanism comprises two like fluidpressure supply and release valve devices, and 2|, the device 20 beingoperative to control the pressure of fluid in pressure chamber I1through the medium oi a passage 22, while the device 2| is operative tocontrol the pressure of fluid in pressure chamber I8 by way of a passage23.

Each of the valve devices 20 and 2|, comprises a bushing 24 pressed intothe casing and open at one end to a chamber 25 which may be in constantcommunication with the atmosphere through a fluid pressure releasepassage 26, and open at the opposite end to a chamber 21 arranged to besupplied with fluid under pressure through a passage 28. Surrounding thebushing 24 in the valve device 20 is cavity 29 open to passage 22, whilesurrounding said bushing in the valve device 2| )is a similar cavity 30open to passage 23. y

Each of the bushings 24 has an axial bore connecting pressure chamber 21to a chamber 3| in the bushing which chamber 3| is connected through oneor more ports 32 to the annular cavity 29 or 39 encircling the bushing.Slidably mounted in each bore is the iluted stem 33 oi a fluid pressuresupply' valve 34 disposed in chamber 21 and arranged'to seat against theend oi the bushing to thereby control communication betweensaid chamber'and chamber 3| within the bushing. Each of two springs 38 in chamber 21acts on one of the supply valves 34 for urging Ysame to its closedposition, i. e., seated against the end of the bushing 24.

The chamber 3| in each bushing 24 constitutes one end of a boreextending through the bushing and opening at one end to chamber 26, andslidably mounted in this bore is a plunger 38 which has an axial passage31 open at one end to chamber 3| and at the opposite end to a radialpassage 38 opening to chamber 25. On the end of the supply valve stem 33which extends into the chamber 3| is formed a release valve 39 arrangedto cooperate with the plunger 36 around the periphery of the axialpassage 31 for controlling communication between chamber 3| and chamber25 which is open to the atmosphere. A spring 40 in chamber 3| issupported at one end on the bushing while the opposite end bears againstthe plunger 36 urging same in the direction away from the release valve39.

Each of the plungers 36 is provided with a portion 42 of reduceddiameter in which the radial passage 38 is formed and which freelyprojects through a central opening provided in a stop 43 which issecured to the end of the bushing. This stop is provided for engagementby a plunger to limit outward movement thereof under the action ofspring 40.

An operating shaft 45 disposed midway between portions 42 oi the twoplungers 36, and extending at right angles to their axes is journaled atopposite ends in the housing. Keyed to this shaft in chamber 25 is anoperating member 46 having two oppositely arranged arms 41 one disposedover each of the plungers 36. An operating screw 48 is mounted in eachof these arms, one screw for engaging the end of plunger 36 in the valvedevice 20 while the' other is arranged to engage the end oi plunger 36of the valve device 2|. Each of these adjusting screws is secured in anadjusted position by a lock nut 49 which is tightened against therespective arm. Outside of chamber 25 an operating lever 59 is securedto one end of shaft 45 for rocking same in either one direction or theopposite direction.

With the lever 50 in a neutral position. such as shown in Fig. 1, and inwhich it will be substantially at tright angles to the power piston rodboth adjusting screws 48 are adjusted so that plungers 36 in the twovalve devices 20 and 2| will be positioned just out of contact with therelease valves 39, as shown slightly exaggerated in Fig. 1. When soadjusted, the pressure chamber |1 at one side of the power piston I0will be opened tothe atmosphere through passage 22 and past the releasevalve 39 in the valve device 20, while pressure chamber I8 at theopposite side of said piston will be open to the atmosphere throughpassage 23 and thence past release valve 39 in the valve device 2 I.

Rocking4 of the lever 50 out of neutral position d chamber I1 will lbeopened past said release valve to atmosphere.v y v,

Likewise, movement of lever I5 from neutral position in acounterclockwise direction, as viewed in Fig. 1, will rst seat therelease valve 39 and then open the supply valve 34'in the valve device2i to thereby permit fluid under pressure to ilow from pressure chamber21 to pressure chamber I8 at the right-hand side of the power piston -I0for moving said piston in the direction ci the lett-hand, while returnof said lever to neutralposition will open chamber i8 to the atmospherepast the release valve 39 in the valve device 2|. f

When either o! the valve devices or 2l is operated to supply iluid underpressure to chamber I1 or I8, respectively, as just described,

plunger 36 in the other valve device is moved outwardly by spring 40into contact with stop 43 thereby maintaining the respective releasevalve 39 open, opening the respective piston chamber I1 or I8 to theatmosphere. aswill be apparent.

The unloading device 1 comprises two coaxially arranged oppositelyseating poppt valves 53 and 56 contained in a chamber' 55 which is openthrough passage 28 to chamber 21 in the iluid pressure control mechanism8. These valves en gage each other in chamber 55 for movement in unisonThe valve 53 has a stem 56 extending into a chamber 51 which, in use, isintended to be constantly supplied with fluid under pressure from anysuitable source by way of a supply pipe 58. The valve 53 controlscommunication between chamber 51 and chamber 55 and when open will allowthe ow'of fiuid under pressure from pipe 59 to chamber 21 in the fluidpressure control mechanism, and when closed or seated will cut-ofi suchflow of iluid under pressure. A spring 69 in chamber 51 acts on stem 56of the supply valve 53 for unseating same and for seating the releasevalve 54.

The release valve 54 is provided with a uted stem 60 extending `into achamber 6I which is in constant communication with the atmospherethrough a passage 6,2, a chamber 63, and a passage 64. This valve isprovided for closing communication between chamber 55 and theatmospheric chamber 6I when the supply valve 53 is open, and for openingsaid communication upon closure of the supply valve 53 for therebyopening chamber 21 in the uid pressure control mechanism to theatmosphere.

The unloading device 1 further Icomprises a movable abutment preferablyin the form oi a iiexible diaphragm 66 which is clamped around itsperiphery between the casing and a cover 61. Chamber 63 is formed at oneside of the diaphragm 66 and contains a follower member 68 which engagesthe diaphragm and which has a stem 69 vdepending therefrom forengagement with stem 69 of the release valve 5B. When the diaphragm isin its normal position shown, as defined by engagement with a stop 19extending into a pressure chamber 1I formed at the opposite side of saiddiaphragm, there preferably is a slight space between the end of stem 69and stem 8l o! the release valve Il when said valve is seated, as shownin the drawing.

Chamber 63 also contains a control spring 12, one end of which lbearsagainst a seat 13 which is slidably mounted on the stem 39 in contactwith the diaphragm follower 69. The opposite end of spring 12 issupported on an adjustable seat 14 which is carried by a plurality ofspaced struts 15, only one oi' which is shown in the drawing. Thesestruts extend through suitable bores in the casing and their oppositeend s are engaged by an adjusting nut 16 having screw-threadedengagement with anl extended portion of the casing. Adjustment of thenut 16 is arranged to act through the struts 15 to move the spring seat1l Vagainst the spring 12 to thereby obtain a desired force of saidspring on the diaphragm follower member 68 to oppose movement thereof inthe direction of the poppet valves 53 d I54. A lock nut 11 is providedon the casing e tension for engaging the adjusting nut 18 to securesamein adjusted position.

Pressure chamber 1I above the diaphragm 66 is open through a passage 18to a timing chamber 19 formed in the cover 61.

The timing chamber 19 is open to a passage 82 connected to the pilotportion 5 of the motor through two parallel passages one containing achoke 80 andthe other containing a check valve 8| arranged to preventilow of fluid in the Adirection from passage B2 to cham-ber 19 but toallow flow in the opposite direction. It will thus be seen that flow offluid'in the direction from passage 82 to chamber 19 will-be restrictedby choke 80 while iiow in the opposite direction may occur by way of thecheck valve 8l as well as through the choke 89 and thus at a more rapidrate.

The pilot portion 5 of the motor comprises a cylinder 85 having a piston.bore 86. One end of the cylinder 85 is open, and secured over this endis a cup-shaped pressure head 91. A pilot piston 88 is mounted to slidein the bore 88 and is rigidly connected `to one end of a piston rod 89which extends through the pressure head 81 parallel to the piston rod II.

The pilot piston 89 comprises two pressure heads 89 and 9| which arespaced apart and integrally connected, and between these heads is achamber 92 which is in constant communication with the atmospherethrough a passage 93 provided in the piston rod 89. At the opposite'sideof pressure head 9 9 is a pressure chamber 94, and a suitable packingcup 95 secured to said pressure head and having sliding contact withAthe wall of bore 86, is provided to prevent leakage of iluid underpressure from chamber 9 4 to chamber 92. The pressure head 9| has at itsopposite face a pressure chamber 96 containing an oppcsitely arrangedpacking cup 91 secured to said pressure head and having sliding contactwiththe Wall 'of bore `81 for preventing leakage of fluid under pressurefrom chamber 96 to chamber 92.

The pressure chamber 94 is connected tc a control pipe 98 through whichfluid under pressure may be supplied to and released from said chamberfor acting on one side of the piston 88. Pressure chamber 96 at theopposite side of the pilot piston is connected to a control pipe 99through which iluid under pressure may be supplied to and released fromsaid chamber for acting cn the right-hand face of the pilot piston.

The two pipes 98 and 99 may be connected to any .suitable control devicearranged to open one of said pipes to the latmosphere while varying thepressure of fluid in the other pipe. A control device of this type isshown and fully described in the copending application hereinbeforereferred.

Two stops and |0| are slidably mounted on the pilot piston rod 88 withinpressure chamber 84. One end of stop |00 engages the piston head 88andat its opposite end has an out-turned annular flange |02 arranged tocooperate with an annular shoulder |08 in the cylinder 88 to limitmovement thereof in the direction o! the righthand. The stop |0| isprovided with an annularin-turned shoulder |00 at one end arranged tocooperate with the shoulder on the pilot piston rod 88 for moving saidstop in the direction oi' the right-hand upon corresponding movement ofthe piston rod 88 from the position shown. The opposite end of stop |0|is arranged to engage a shoulder in the pressure head 81 as shown inFig. l to limit movement of the stop in the direction of the left-hand.A coil spring |08 under initial compression and encircling the pistonrod 88 bears at one end against the stop |00 and at the opposite endagainst the stop |0|.

From the above description it will be seen that in case of movement ofthe pilot piston 88 and rod 88 in the direction of the right-hand thestop |0| and engaging end of control spring |05 will move with said rod,but the stop |00 will remain stationary, and such movement of saidpiston will therefore be opposed by said spring and will be limited bycontact between stop |0| and a ring |08 clamped between the cylinder 85and pressure head 0. Upon movement oi' pilot piston 80 and rod 88 in thedirection of the left-hand, the stop |0| will remain stationary whilethe stop |00 will move with said piston so that spring |05 will opposethis movement which will be limited by engagement of stop |00 with thering |08. Engagement between stop |00 and shoulder |08 in the cylinderand between stop |0| and the pressure head acts to limit expansion ofspring |05 and will therefore denne aneutral position of the pilotpiston, in which said piston is shown in the drawing.

The end of the pilot piston rod 88 is connected by a pin |01 to a lever|08 intermediate ilts ends. One end of this lever is connected to oneend of a link |08 by a pin ||0 and the opposite end of this link :lsconnected to pin I3 in the .end of the power piston rod The opposite endof lever |08 is connected by a pin to oneend of a link ||2, the oppositeend of which is connected by screw-threads to one end of a reach rod||8. The opposite end of the reach rod is adjustably connected to oneend of a link ||4, the other end of which is connected by a pin ||5 tothe free end of lever 50 in the fluid pressure control mechanism 8. Thereach rod ||8 extends between two jaws ||8 projecting from the pilotpiston cylinder 85. At one side of the jaws ||8 a stop nut |2| isadjustably mounted on the reach rod by screwthreads for engaging saidjaws. while a like nui |22 is mounted on the reach rod at the oppositeside of the jaws for engagement therewith. The stop nuts |2| and |22 arelocked to the reach rod I8 in adjusted conditions by suitable lock nuts|28.

The two adjusting nuts |2| and |22 are sa adjusted on the reach yrod ||8as to limit movement of said rod in either direction from a neutralposition shown in the drawing, to a degree Just sulcient to actuate thelever 50 of the fluid pressure control mechanism 8 in either directionfrom its neutral position to seat therelease valve 88 and open thesupply valve 80 of the fluid pressure supply and release valve device 20or 2|.

Operation.

With chambers 88 and 88 at opposite sides of the pilot piston 88 bothvented or open to atmosphere, the pilot piston will assume a neutralposition. as shown, under thelaction of spring |08. With the pilotpiston thus positioned, the parte of the fluid pressure controlmechanism 8 will also assume the positions shown opening pressurechambers |1 and |8 at the opposite sides of the power piston I0 toatmosphere, and the power piston and thereby the clutch control arm willassume their neutraP' position shown for reasons which will be laterbrought out.

Alsol with the pilot piston 88 in its neutral position, the timingchamber 18 and diaphragm chamber 1| in rthe unloading device 1 will beopen to atmosphere by way of passage 82, chamber 82 between piston heads80 and 8| of said piston and passage 88 'in piston rod 88. Controlspring 12 in the unloading device will therefore be effective to holdthe diaphragm 88 and follower 68 in their normal positions shown in thedrawing `which permits closure of the release valve 84 and opening ofsupply valve 88 by spring 80. Fluid under pressure will therefore besupplied from pipe 88 to chamber 21.

If now itis desired rto eiIect movement of the clutch control arm 8 fromneutral" position to forward position, fiuid under pressure is suppliedthrough pipe 88 rto chamber 88 at one'side of the pilot piston 88, whilechamber 88 at the opposite side is maintained opened to atmospherethrough pipe 88. When fthe pressure of fluid thus supplied to chamber 84and acting on one side of the pilot piston 88 becomes increased to adegree sufilcient to overcome the opposing force of spring |05 onfollower |0|, said piston will move inthe direction of the right-hand.The piston 88 acts through the piston rod 89 on the lever |08, and dueto relatively greater reluctance to movement of the power piston I0, themovement of piston 88 will turn the lever in a clockwise direction aboutits fulcrum connection, at pin ||0 with the power piston rod and thusmove the reach rod ||8 in the direction of the right-hand, to a positiondenned by contact between the regulating nut |2| and jaws ||8, whichthen holds the pilot piston against further movement. This movement ofthe reach rod ||3 however rocks the arm in the fluid pressure controlmechanism 6 in a clockwise direction as viewed in Fig. 1 to a deg-reesufficient for actuating :the supply and release valve device 20 tosupply nuid under pressure from pressure chamber 21 to chamber |1 at theleft-hand side of the power Piston I0, while the supply and releasevalve device 2| maintains chamber I8 at the opposite side of the powerpiston open to atmosphere. The pressure of uid .this supplied topressure chamber I1 at one side of the power piston I0 then effectsmovement thereof in the direction of the right-hand and this movementpulls the clutch control arm 8 taint of neutri-il" position towardforward" posi- When the power piston I0 moves under the `influence ofuid pressure in pressure chamber maintained open even upon a maximumdegree two pistons thus conftinue to move together until thev clutchcontrol arm 3 attains substantially its forward position, at which timethe pilot piston 88 opens passage 82 to chamber 94. This opening ofpassage 82 to chamber 94 preferably occurs Just before the pilot piston88 attains its extreme-rlght-hand position defined by contact betweenthe follower 'and the stopring |06. When passage 82 is thus opened topressure chamber 84, fluid under pressure then ilows from aid chamberthrough said passage and choke 80 o timing chamber 19 and diaphragmchamber 1| in the unloading device 1, and when the pressure of fluidthus obtained in chamber 1| becomes increased to a degree suicient toovercome the opposing force of control spring 12, the diaphragm 88 isdeflected in a downwardly direction and unseats the release valve 54 andseats the supply valve 53. The seating of the supply valve 53 cuts oilfurther supply of fluid under pressure to pressure chamber 21 in thefluid pressure control mechanism 8 and thereby t'o the connectedpressure chamber |1 at the left-hand side of the power piston I0, whileopening of the release valve 54 opens said chambers to atmosphere fortherebyrelieving the power piston |0 of the pressure oi iluid inchamberi1, in order to relieve the clutchl control arm 3 and thereby the thrustbearings in the'clutch controlled by said arm of operating Aforce.

or movement of the power piston |0 relative to the pilot piston'88, inorder that the unloading valve device 1 may operate to release'iluidunder pressure from the power pistonl chamber I1 and thus relieve theclutch arm 3 of actuating force,

The movement of the pilot piston 88 by presn sure or iiuid in chamber 94is stopped by vfollower |0| engaging the stop ring |06 immediatelyfollowing the opening oi' passage 82 to pressure chamber 94, as abovedescribed, and the regulating nut |2| on the reach rod ||3 is soadjusted as to prevent the pilot piston 88 obtaining this extremeposition beforethe power piston I0 attains the position in which arm 3is substantially in its forward position. The choke 80 restricting theflow of fluid under pressure to the timing chamber 19 is provided tothen delay operation of the unloading valve device 1 to release iluidunder pressure from the power piston chamber` i1, after the pilot pistonceases movement and the clutch control arm 3 is in orsubstantially inits forward" position, in order that such pressure on the power pistonmay continue effective for a.l

period of time` which will insure complete stroking, or further movementof the power piston, it

necessary, to insure that the clutch control arm 3 is moved to itsforward" position regardless of variable 'conditions in the clutch whichmay act to delay or oppose the desired positioning of the clutch arm 8.

After the pilot piston 88 is stopped in its righthand position, theremay be a slight continued movement of the power piston |0 relative tosaid pilot piston as above mentioned and such movementwill act to rockthe lever |08 in a counterclockwise direction about itsfulcrumconnection with' the pilot piston rod 89 and thus operate the reach rodI3 to turn lever 50 of the uid pressure as above'described.

If the-operator now desires to return the clutch control arm 8 fromforward position to neutral" position, he opens pipe 98 to atmospherefor thereby releasingthe iiuid under pressure from pilot piston chamber94, and as long as passage 82 remainsopen to chamber 94, iiuid underpressure will also be releasedfrom chamber 19 in the unloading valvedevice 1 by way of check valve 8| and through chamber` 94. When thepressure oi iluid in chamber 84 is `thus suiliciently reduced, the forceof spring |05 on stop |0| moves the pilot piston 88 relative to thepower piston |0 in the direction of the left-hand to thereby operate thelever |08 to pull the reach rod ||3 in the same direction until theregulating nut |221y engages the laws H8. This movement of the pilotpiston. 88 -opens passage 82 to' the atmospheric chamber-92 between thetwo piston heads 80 and 9| of said piston whereupon further release offluid under pressure from timing chamber 18 and diaphragm chamber 1| inthe unloading device 8 occurs by way of chamber 82. The release of uidunder pressure from the timing chamber 19 and diaphragm chamber 1| willoccur rapidly by way of the check valve 8| and when such Vpressure issufficiently reduced. the control spring 12 returns the "diaphragm 98and follower 88 to their normal positions shown therebyJ allowing. therelease valve 54 to close and the supply valve 53 to open. Fluid underpressure from the supply pipe 58 then again ows to the supply chamler 21in the uid pressure control mechanism i,

Movement of the reach rod ||3 to the position defined by engagement ofregulating nut |22 with jaws, ||8 operates the arm 50 in the uidpressurecontrolmechanism 6 in a counterclockwise direction as viewed inFig. 1 to thereby actuate the' valve device 20 to open pressure chamber|1 at one side of the power piston I0 lto atmosphere and at the sametime actuates the valve device 2| to supply fluid under pressure fromthe supply chamber 21 to pressure chamber 8 at the opposite side of thepower piston. The pressure of fluid thus supplied to chamber I8 thenacts to move the power piston I0 in the direction of the left-hand, forthereby rocking the clutch control arm 3 from its forward position inthe direction of its neutral position.

At the time the power piston I0 starts moving from'eits extremeright-hand position in the direction of the left-hand, the pilot piston88 will control mechanism 6. This movement of thelever 50 will bein acounterclockwise.direction which will move regulating Inut |2| on thereach rod out of contact with the jaws |8 and will then continue untilthe power piston 0 ceases movement. For the maximum degree of movementof the power piston i0 after the pilot piston 88 stops moving, thecontrol lever 50 in the iiuid pressure control mechanism 6 will no t beoperated however suiciently to allow closing of the supply valve 34 inthe valve device 20. In other words. the supply valve 34 in the valvedevice 20 will be be to the right of its neutral position shown and lthe reach rod ||3 will be in a position deiined byunder the action ofspring |05. The two pistons thus continue to move together until thepilot. piston 88 attains its neutral position in which it will then beheld by the force of spring |05. Fur--` ther' movement of the powerpiston |0 under pressure of fluid in chamber I8 will then rock the lever|88 in a clockwise direction about the ful-- crum pin |01 connected tothe pilot piston rod tuating force.

88 and this movement of said lever will move the reach rod H3 in the`direction o the right-hand and return the lever 50 in the fl d pressurecontrol mechanism 8 back toward its neutral position. The lever 50 willattain its neutral position at substantially the time the power piston Iand thereby clutch arm 3 attain their "neutral" positions, and the valvedevice 2| in the mechanism 8 will therefore be operated to cut off thesupply of fluid under pressure to the pressure chamber I8 and to opensaid chamber to atmosphere for thereby relieving the power piston I0 ofactuating force. The power piston I0 will therefore be stopped in itsneutral position shown for neutraliz'ing the clutch control arm 3.

If the operator now desires to move the clutch control arm 3 from its"neutral Vposition to its reverse position, he supplies fluid underpres- 4sure through pipe 89 to pressure chamber 98 at the right-handside of the pilot piston 88 while retaining chamber 90 at the oppositeside open to atmosphere to the pipe 98. As a result, the pilot piston 88initially moves toward the left-hand relative to the power piston I0 forthereby operating lever |08 to pull the reach rod I I3 toward theleft-hand to a position defined by contact between the regulating nut|22 and the jaws I I8.

This operation of reach rod H3 rocks the lever 50 in the fluid pressurecontrol mechanism'8 in a counter-clockwise direction for actuating thevalve device 2| in said mechanism to supply fluid under pressure topressure chamber I8 while allowing the valve device to remain in thecondition opening pressure chamber |1 to atmosphere.` The power pistonI0 is then moved by pressure of iluid lin chamber I8 in the direction ofthe left-hand and rocks the clutch control arm 3 from its "neutraPposition toward its reverse position. During this movement of the powerpiston I0 the pilot piston 88 moves therewith in the same manner asabove described, and Just before contact between follower |00 and stopring |08, the pilot piston opens communication between passage 82 andpressure chamber 88. This occurs at substantially the time the powerpiston I0 has moved the clutch control arm 3 to its reverse position.following which the unloading device 1 operates in the same manner asbefore described to cut-oi! the supply of fluid under pressure topressure chamber I8 and to open said chamber to` atmosphere, for therebyrelieving the power piston I0 and clutch control arm 3 of ac- To nowmove the clutch control arm 8 from "reverse" position back to "neutralposition, fluid pressure is released from pressure chamber 98 at oneside of the pilot pIston by way of pipe 99.

and Jaws H8 turns lever 50 of the1 fluid pressure control mechanismin a.clockwise direction as viewed in Fig. l for thereby operating th'e valvedevice 20- therein to supply fluid under pressure to pressure chamberI1, while the valve device 2| remains in the condition opening pressurechamber I8 to atmosphere. Pressure of fluid thus supplied to chamber I1then moves the power piston I0 in the direction of the righthand forpulling the clutch control arm 3 from its reverse" position in thedirection of neu-` tral position. The initial movement of the powerpiston I0 out of its left-hand position rocks lever |08 about itsfulcrum connection with reach` rod I3 to allow the pilot piston 88 to bereturned to its neutral position shown under the action of spring |05.Following this, the lever |08 rocks about the pin |01 to return thereach rod H3 to its neutral position for thereby operating the fluidpressure control mechanism 8 to vent the fluid pressure from pressurechamber I1 at substantially the time the power piston and thereby theclutch control arm 3 attain their neutral positions, for therebystopping said piston and arm in such positions.

If the clutch control arm 3 should occupy its forward position and itshould be desired to move said arm from "forward position to reverseposition without stopping in neutral position, fluid under pressure isvented from pressure chamber 94 at.one side of the pilot piston 88 byway of pipe 98, and at the same time fluid under pressure ,is suppliedthrough pipe 99 to pressure chamber 98 at the opposite side of saidpiston. As a result, th'e combined action of spring |05 through follower|0| on the pilot piston 88, and the increase in pressure in chamber 98at the opposite side of the' pilot piston is initially effective tomoveisaid piston relative to the power piston |0 to the position inwhich passage 82 is open to the atmosphere by way of chamber 92 betweenthe two piston heads 90 and Spring I05-then moves the pilotpiston 88 inthe Y direction of the right-hand for rocking thelever |09 to move thereach rod H3 in the same direction to a position defined by theregulating nut |2I contacting the jaws H8. This movement of the pilotpiston 88 relative to the power piston I0 again closes communicationbetween passage 82 and pressure vchamber 88 and opens said passage tochamber 92 between the two-piston heads 90 and 9| for thereby venting.uid under pressure from the timing chamberv19 and diaphragm chamber 1|in the unloading device 1 whereupon said device operates to again supplynuid under pressure to the supply chamber 21 in the fluid pressurecontrol mechanism 8 in the same manner as before described.

Movement of the reach rod H3 to the position 9| and in which theregulating nut |22 on the reach rod H3 engages the iaws H8. As a result,the unloading device 1 operates as above described to again open thefluid pressure supply connection between the supply pipe 58 and chamber21 in the uid controlled mechanism 8. and the arm 50 in said mechanismactuates the valve device 2| therein to supply fluid under pressure tochamber I8 while the valve device 20 therein remains in the conditionopening pressure chamber |1 to the atmosphere. As a result, the piston|0 will be caused to move in the direction of the left-hand fortherebyrocking the arm 3 out of its "forward" position in the directionof its reverse position. As the power piston thus moves, the pilotpiston 88 moves therewith under the pressure of fluid in chamber 98 andnally against i the opposing force of spring |05 until said pilot pistonattains substantially its left-hand position and ring |08. In thisleft-hand positi'on of the pilot piston fluid under pressure is suppliedfrom pressure chamber 98 through passage 82 to the unloading valvedevice 1 for effecting operation thereof to release fluid under pressurefrom pressure chamber I8. This release of pressure from chamber I8 willoccur at substantially the time the power piston I0 attains its extremeleft-hand position or slightly thereafter in the same manner as abovedescribed, in order to insure that th'e clutch control arm 3 will be inits "reverse" position. i

Upon supply of fluid under pressure to pipe 88 and thel opening of pipe99 to atmosphere the fluid motor will operate to move the clutch controlarm 3 from its reverse position to its "forward position in a mannerwhich will be ap parent from the above description.

In the operation above described it will be noted that the regulatingnuts |2| and |22 limit the initial movement of the pilot piston 88relative to the power piston I to a degree suillcient to actuate the uidpressure control mechanism 6 to supply iluid under pressure either topressure chamber il at one side of the power piston or pressure chamberI8 at the opposite side, `but insuillcient to open passage 82 to chamber94 or 96, whichever is supplied with fluid under pressure for moving thepilotpiston. The passage 62 is connected to the pressure cha` ber 94 or96 by the pilot piston only after the power piston has moved the clutchcontrol ami 2 to substantially its forward position or itsreverse"lposi^ tion, and the purpose of thus delaying the supply offluid to the timing chamber 'I9 in the unloading device 'l is to permitthe use of a timing chamber of minimum size with respect to a practicalsize of choke 80.

If it should be desired to arrange the motor to control operation of aclutch in which the movable part has less travel than in the clutchabove described and which would therefore limit the movement of controlarm 8 to positions such as indicated by legends A and B indicating theforward and reverse" positions oi the speciilc clutch, it will be seenthat movement of the power piston I0 will be correspondingly reduced.With the regulating nuts |2| and |22 adjusted as above described, thisreduced stroke of the power piston i0 would therefore be inadequate toallow the pilot piston 88 to move to either extreme position for openingpassage 82 to pressure chamber 94 or pressure chamber 96. As a result,the unloading valve device 1 could not operate to relieve the powerpiston and thereby the clutch operating arm of actuating force. To meetthis condition the regulating nuts |2| and |22 may therefore be adjustedaway from each other to a degree sumcient to allow .the pilot piston 88to obtain either of its extreme positions for opening passage 82 topressure chamber 84 or 96 with theV power piston i0 in either of itsextreme positions deiined by the clutch operating parts having thereduced travel. When the regulating nuts are so adjustad, the iluidmotor will operate to control the positioning of the clutch arm 3 havingForward and Reverse" positions such as indicated by the legends A and B,in the same manner as above described.

Summary From the above description it will now be seen that I haveprovided a iiuid motor for moving a member, like the movable part of aclutch, to any selected one or' its positions and which then operatesautomatically to remove the actuating force to avoid damage tothe-"operated parts. The unloading means for removing the actuatingforce is controlled substantially .in accordance with the position ofthe power piston and thus maintained against operation until the clutchpart has substantially obtained the desired position in order to insuresuch positioning. A novel arrangement is provided for thus delayingtheoperation of the unloading means,.and the arrangement is adjustable toobtain the same recult for different operating strokes of the powerpiston required i'or controlling different clutches the movable parts ofwhich have different degrees of travel.

Having now described my invention, what l. claim as new and desire tosecure by Letters Patent, is:

1. In combination, a movable abutment movable by pressure of fluid in achamber, valve means operable to supply fluid under pressure to saidchamber, a valve device arranged to control said 'supply of fluid underpressure to said chamber and operable to cut oil' such supply and tovent fluid under pressure from said chamber, actuating means operableupon movement relative to said abutment to effect operation of saidvalve means and upon further movement to 'a certain position to effectoperation of said valve device, control means connecting said actuatingmeans to said valve means and abutment `pro viding for movement of saidactuating means relative to said abutment to ,eilect operation of saidValve means, and adjustable means included in said control meansoperable to limit movement of said actuating means relative to saidabutment to a degree for eiecting operation of said valve means and thenproviding i'or further movement 'of said actuating means with saidabutment, and adjustable to provide for said actuating means obtainingsaid certainl position in a chosen'position of said abutment. Y

2. In combination, a power abutment movable upon supply of iluid underpressure to a chamber, valve means operable to supply iluid underpressure 'to said chamber, a valve device operable to cut oi! saidsupply oi fluid under pressure to said chamber and to vent fluid underpressure from said chamber, a pilot abutment movable by fluid underpressure, actuating means connecting said valve means to said power andpilot abutments providing for movement of said abutments relative toeach other and in unison, said pilot abutment being movable by fluidunder pressure to first actuate said`valve means and then to a certainposition to effect operation of said valve device, said actuating meansincluding adjustable means operative to limit movement of said pilotabutment by fluid under pressure relative to said power abutment andthen providing for movement of said pilot abutment with said powerabutment, said adjustable means being adjustable to provide for saidpilot abutment obtaining said certain position in a chosen position ofsaid power abutment.

3. In combination, a power abutment movable upon supply of uid underpressure to a chamber, valve means operable to supply iiuid underpressure to said chamber, a valve device operable'to cut oil said supplyof yfluid under pressure to said chamber and to vent fluid underpressure from said chamber, a pilot abutment movable by iluid underpressure, actuatingmeans connecting said valve means to said power andpilot abutments providing for movement of said abutments relative toeach other and in unison, said pilot abutment being movable by fluidunder pressure-to first actuate said valve means and then to a certainposition to effect operation of said valve device, said actuating meansincluding lever means operatively connected to said pilot and powerabutments, and a rod connecting said lever means and valve means, iixedstop means, and adjustable stop means associated with said rod andarranged to engage said fixed stop means in a position of said pilotabutment eil'ecting operation of said valve means to prevent furthermovement of said pilot abutment relative to said power abutment andproviding for said pilot abutment obtaining said certain position in achosen position oi' said power abutment.

4. In combination, a power abutment movable upon supply oi' fluid underpressure to a chamber. valve means operable to supply fluid underpressure to said chamber, a valve device operable to cut ofi said supplyof fluid under pressure to said chamber and to vent fluid under pressurefrom said chamber, a pilot abutment movable by fluid under pressure, alever having one connection with said power abutment and anotherconnection with said pilot abutment, a rod for actuating said valvemeans connected to said lever, fixed stop means, adjustable stop meanson said rod arranged to cooperate with said fixed stop means to limitmovement of said rod to a position for actuating said valve means, saidpilot abutment being movable by iiuid under pressure relative to saidpower abutment to actuate said lever and thereby said rod to saidposition, and being then movable with said power abutment relative tosaid rod and being operative in a chosen position of said power abutmentto effect operation of said valve device.

5. In combination, a double acting power-.piston, a valve devicecomprising an operating member having a first position for supplyingfluid under pressure from a chamber to one side of said power piston formoving same in one direction and having a second position for supplyingfiuid under pressure from said chamber to the opposite side of saidpower piston for moving same in the opposite direction, valve meansoperable to supply fluid under pressure to said chamber and alsooperable to out of! such supplyand open said chamber to atmosphere, apilot piston, a lever connecting said pistons, a rod connecting saidlever to said valve device, said pilot piston being operable uponmovement relative to said power piston in one direction to actuate saidlever and rod to move said operating member to its said first positionand in the opposite direction to actuate said lever and rod to move saidoperating member to said second position, said pilot piston being alsomovable in said one direction after said operating member is in saidfirst position to one unloading position and in said opposite directionafter said operating member is in said second position to anotherunloading position, means arranged to limit movement of said pilotpiston to the two unloading positions, means operable upon movement ofsaid pilot piston to both of said unloading positions to effectoperation of said valve means to cut on the supply of fluid underpressure to said chamber and opensaid chamber to atmosphere and operablewith said pilot piston out of said unloading positions to effectoperation of said valve means to supply fluid under pressure to saidchamber, fixed stop means. and adjustable means on said rod arranged tocooperate with said fixed stop means to limit movement of saicPpilotpiston in both directions relative t said power piston to positions forpositioning said operating member in either its said first or secondpositions, said lever then providing for movement of said pilot pistonwith said power piston, and said adjustable means providing for said.pilot piston obtaining its said unloading positions in chosen positionsof said power piston.

6. In combination, a double acting power piston, a valve devicecomprising an operating member having a neutral position for openingopposite sides of said piston to atmosphere, a

forward position for opening communication between a chamber and oneside of said piston for suppiyingiuid under pressure to. act on saidpiston to move same in one direction, and a reverse position for openingcommunication between said chamber and the opposite side of said pistonfor supplying uid under pressure to act on the piston for moving same inthe opposite direction, unloading means operable to supply fluid underpressure to said chamber and also operable to cut ofi such supply offluid under pressure and to open said chamber to atmosphere. a pilotpiston, a lever connected to said power piston and to said pilot pistonproviding for movement of said pistons relative to each other and inunison, a rod connecting said lever to said operating member, said pilotpiston having a neutral position and being operable uporr movementtherefrom in one direction to actuate said lever and rod to move saidmember to said forward position and being then further movable to oneunloading position, and being op-` erable upon movement in the oppositedirection from neutral position to actuate said lever and rod to movesaid member to said reverse position and being then further movable to asecond unloading position. means controlled by said pilot pistoncontrolling said unloading means and operable in said unloadingpositions of said pilot piston to effect operation of said unloadingmeans to cut of! the supply of fluid under pressure to said chamber andto open said chamber to atmosphere and operable with said, pilot pistonout of said unloading positions to eect operation of said unloadingmeans to supply fiuid under pressure to said chamber, fixed stop means,adinstable stop means on said rod arranged to cooperate with said fixedstop means upon movement of said pilot piston relative to said powerpiston in either direction from neutral position to limit such movementto a degree providing for moving said operating member to either itsforward or reverse position and then providing for said pilot pistonobtaining said unloading positions upon further movement with said powerpiston in chosen positions of said power piston, means operative to movesaid pilot piston from either of its unloading positions to said neutralposition, said pilot piston being operable upon movement from eitherunloading position to neutral position to eect movement of saidoperating member to either forward position or reverse position, andsaid power piston being1 then operable to effect movement of saidoperating member to its neutral position in a position of said powerpiston corresponding to neutral position of said pilot piston.

WILLIAM H. GLASS.

